WWF strongly supports the recommendation of the Mekong River Commission’s Strategic Environmental Assessment for a ten-year deferral on the construction of any of the 11 hydropower dams proposed for the lower Mekong river mainstream in Laos, Thailand and Cambodia.

“The social and environmental damages likely to be caused by any one of the mainstream dams are of a scale that cannot be ignored, they are much higher than any tributary dam,” said Marc Goichot, Senior Sustainable Infrastructure Advisor for WWF Greater Mekong.

“We need this ten-year deferral so innovative technology, tailored made to the unique conditions of the Mekong, can be developed to allow for energy production without high risk to the river and the people dependent on its resources,” he said.

The report says if any dam were constructed on the lower Mekong river mainstream it would sever ecosystem connectivity jeopardizing the livelihoods and food security of tens of millions of people living in Laos, Cambodia, Thailand and Vietnam.

If any of the 11 proposed lower Mekong mainstream dams were built they would accelerate and heighten the negative impacts of the existing upper Mekong Chinese dams. The blockage of sediment and nutrient flows downstream is very likely to trigger erosion of the riverbank and Mekong delta, significantly reducing the productivity of lower Mekong freshwater and marine fisheries worth billions of dollars to Mekong economies annually.

Moreover, the report says if the lower mainstream dams go ahead globally endangered species such as the Mekong giant catfish will be driven to extinction. Currently, the Mekong river is home to more giant fish than any other river on the planet and is second only to the Amazon river for fish biodiversity.

“In the case of the Mekong, mitigation plans are not yet proven to be effective. Deferring construction of these dams is an opportunity to benefit from the latest knowledge, and thus leapfrog into sustainable development,” said Mr Goichot.

The SEA will guide the MRC process of notification, prior consultation and agreement, and ultimately support national decisions on whether to proceed with the construction of the dams including the recently notified Sayabouly dam in northern Laos.

The SEA highlights one innovative hydropower alternative to mainstream dams called Thakho proposed by the Lao Department of Electricity and French company CNR (Compagnie Nationale du Rhone) in southern Laos. Thahko is the twelfth hydropower project assessed in the MRC SEA report.

The proposed Thakho project is adjacent to the Mekong river at the Khone Phapeng waterfalls, an epicentre for tourism in Laos. It works by diverting some water from the Mekong mainstream into a channel where it passes through turbines and back in to the Mekong downstream.

This project has no dam or reservoir and therefore does not sever ecosystem connectivity, allowing for sediment to flow downstream and fish to migrate. Its integrated design also allows for sustainable tourism development.

The SEA recommends the ten-year deferment period should include a fast tracking of Mekong tributary hydropower projects that are considered feasible and sustainable according to current international good practice, including retrofitting of existing projects.